Usernames with hyphen are rejected in sftpsubsys

[jonasbardino]

As mentioned in the comments to PR #233 existing users with hyphen (-) in their usernames are incorrectly rejected in PAM before even reaching authentication:

Jun 12 09:45:51 sftp-erda pam_mig[73585]: Invalid username: REDACTED@mpifr-bonn.mpg.de
Jun 12 09:45:51 sftp-erda sshd[73585]: Invalid user REDACTED@mpifr-bonn.mpg.de from REDACTED port 40024

We need to allow hyphen in the regex pattern in PAM and NSS and a regression in that PR apparently broke that.

[jonasbardino]

An affected user confirmed the patch to fix the issue in production. Please refer to internal support ticket 34499 for details.